Sodium-taurine cotransport in reptilian renal brush-border membrane vesicles

The coupled transport of Na⁺ with taurine into snake renal brush-border membrane vesicles (BBMV) was studied using 5-s uptake conditions. Taurine transport into snake renal BBMV involved two parallel processes, one saturable (Na⁺-dependent) and one (Na⁺-independent) that behaved like passive diffusion. Below 1 mM taurine concentration, the Na⁺-dependent system accounted for 60% of total taurine uptake. Over both low (0.001–0.80 mM) and high (0.8–5.0 mM) taurine concentration ranges, the Na⁺-dependent taurine uptake within each range showed Michaelis-Menten kinetics, suggesting the presence of two independent saturable Na⁺-dependent transport systems for taurine. The high-affinity, low-capacity system saturated above 100 M with a K _m of 71.4±45.7 M and a maximum velocity (V _max) of 21.9±3.77 pmol (mg protein)^–1 (5 s)^–1. The low-affinity, high-capacity system saturated above 1 mM, with a K _m of 1.11±0.63 mM and a V _max of 252±47 pmol (mg protein)^–1 (5 s)^–1. The stoichiometric relationship between external Na⁺ concentration and taurine uptake (at 10 M) by the high-affinity BBMV transport system was examined by the activation method under short-circuited conditions. The 5-s rate of taurine transport was a sigmoid function of increasing extravesicular Na⁺ concentration. Kinetic analysis of the interaction of Na⁺ with the high-affinity taurine transport system suggested that 3 Na⁺ ions (3.2±0.7) may be involved with 1 taurine molecule in the transport event. The data suggest the presence of a highly efficient and high-affinity reabsorptive taurine transport system on the luminal membrane of the kidney of the garter snake, a species that can secrete taurine in vivo.     

Increase in taurine content before onset of seizures induced by a glutamate decarboxylase inhibitor

Summary The concentration of taurine was measured in 15 brain regions of the rabbit before the onset of convulsions induced by the potent glutamate decarboxylase inhibitor methoxypyridoxine. A significant rise in taurine content was observed in the hippocampus, putamen, caudate nucleus, frontal cortex, thalamus and hypothalamus. GABA levels determined from the same tissue samples were all significantly reduced. An unaffected taurine synthesis coupled with blocked transport to the blood is considered as a possible explanation for this taurine increase.     

牛磺酸对大鼠面神经损伤的疗效观察

目的：探讨牛磺酸对大鼠面神经损伤的治疗作用。方法：制备大鼠面神经损伤的动物模型并将其随机分为两组。牛磺酸组：10％牛磺酸1ml/100mg灌胃，分别于损伤后第14天、28天，检测伤后面神经复合动作电位传导速率、幅度和潜伏期；对照组：用等量的生理盐水灌胃。结果：牛磺酸组动作电位传导速度与对照组相比，有显差异性（P＜0．01）。结论：牛磺酸可促进面神经损伤的恢复。     

1,2-二甲基-3-羟基-4-吡啶酮和牛磺酸联合应用对铝染毒大鼠肾功能及抗氧化系统的保护作用

目的探讨1,2-二甲基-3-羟基-4-吡啶酮(deferipone,DFP)和牛磺酸联合作用对染铝大鼠肾脏功能、抗氧化系统及ATP酶活力的影响。方法将56只SPF级雄性Wistar大鼠按体重随机分为7组,以灌胃方式染毒。其中,阴性对照组给予1.0 ml/d生理盐水,连续8周。前4周,铝染毒组、牛磺酸干预组、低剂量DFP干预组、高剂量DFP干预组、牛磺酸与低剂量DFP联用组、牛磺酸与高剂量DFP联用组均给予281.40 mg/(kg·d)AlCl_3·6H_2O;后4周,各组分别给予1.0 ml/d生理盐水、400 mg/(kg·d)牛磺酸、13.82 mg/(kg·d)DFP、27.44 mg/(kg·d)DFP、400 mg/(kg·d)牛磺酸+13.82 mg/(kg·d)DFP、400 mg/(kg·d)牛磺酸+27.44 mg/(kg·d)DFP。测定大鼠肾脏Na~+K~+-ATP酶、Mg~(2+)-ATP酶、Ca~(2+)-ATP酶、超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)活力和丙二醛(MDA)含量及肌酐(Cr)、尿素氮(BUN)含量。结果与铝染毒组相比,各干预组大鼠肾脏GSH-Px、Na~+K~+-ATP酶、Mg~(2+)-ATP酶活力均明显升高,肾脏MDA含量和血清BUN含量均明显降低,差异有统计学意义(P0.05);且高剂量DFP干预组及联合用药组大鼠肾脏SOD活力明显升高,差异有统计学意义(P0.05)。与单独用药组相比,联合用药组Na~+K~+-ATP酶、Mg~(2+)-ATP酶、SOD、GSH-Px活力明显升高,MDA和血清BUN含量明显降低,差异有统计学意义(P0.05)。各组间Ca~(2+)-ATP酶活力及血清Cr含量无明显差异(P0.05)。结论在一定剂量范围内,与牛磺酸或DFP单独用药相比,牛磺酸和DFP联合用药可以对染铝大鼠肾脏功能及抗氧化系统起到更好的保护作用。     

Risk assessment for the amino acids taurine, L-glutamine and L-arginine

Taurine, glutamine and arginine are examples of amino acids which have become increasingly popular as ingredients in dietary supplements and functional foods and beverages. Animal and human clinical research suggests that oral supplementation of these amino acids provides additional health and/or performance benefits beyond those observed from normal intake of dietary protein. The increased consumer awareness and use of these amino acids as ingredients in dietary supplements and functional foods warrant a comprehensive review of their safety through quantitative risk assessment, and identification of a potential safe upper level of intake. The absence of a systematic pattern of adverse effects in humans in response to orally administered taurine (Tau), l-glutamine (Gln) and l-arginine (Arg) precluded the selection of a no observed adverse effect level (NOAEL) or lowest observed adverse effect level (LOAEL). Therefore, by definition, the usual approach to risk assessment for identification of a tolerable upper level of intake (UL) could not be used. Instead, the newer method described as the Observed Safe Level (OSL) or Highest Observed Intake (HOI) was utilized. The OSL risk assessments indicate that based on the available published human clinical trial data, the evidence for the absence of adverse effects is strong for Tau at supplemental intakes up to 3 g/d, Gln at intakes up to 14 g/d and Arg at intakes up to 20 g/d, and these levels are identified as the respective OSLs for normal healthy adults. Although much higher levels of each of these amino acids have been tested without adverse effects and may be safe, the data for intakes above these levels are not sufficient for a confident conclusion of long-term safety, and therefore these values are not selected as the OSLs.     

牛磺酸和微量营养素干预对人体蛋白营养状况及暗适应功能的影响

目的 :研究低照度作业人员营养干预对血浆蛋白、血浆游离氨基酸含量及夜视功能影响。方法 :驻渝某雷达团战士 34人 ,年龄 1 8～ 2 9岁 ,分为实验组和对照组 ,实验组人员每天加服一定剂量牛磺酸及多种微量营养素。实验期限为 4周 ,分别在服药前、服药 2周及服药 4周检测受试人员快速暗适应时间。结果 :低照度作业人群 ,服用牛磺酸和多种复合微量营养素制剂 2周后 ,快速暗适应功能即大幅度提高 ,服用 4周后效果更佳。营养干预后 ,实验组 PAB、CER、TRF三种血浆蛋白均有所升高 ,而蛋氨酸 ( Met)、异亮氨酸 ( Iie)和亮氨酸 ( Leu)等必需氨基酸含量则降低。结论 :适当补充牛磺酸及 VA、B族维生素、VC、微量元素 Zn、Se能有效提高低照度作业人群暗适应功能     

牛磺酸和鸡冠花乙醇提取物对大鼠血脂及脂质过氧化物的影响

目的探讨鸡冠花乙醇提取物对大鼠血脂、脂质过氧化物及脂肪肝的影响．方法ＳＤ大鼠３０只,２４０±２５ｇ,雄性．随机分为高脂对照组（简称对照组）、牛磺还组和鸡冠花组,每组１０只,各组均喂给高脂饲料,建立高脂动物模型,鸡冠花组通过预防性给予鸡冠花提取物１００ｍｇ／ｋｇ８ｗｋ,牛磺程组给牛磺酸１００ｍｐ／ｋｇ．８ｗｋ,于实验４Ｗｂ和８Ｗｋ测血脂、ＭＤＡ等,并进行比较。结果对照组实验第４Ｗｋ后血脂及ＭＤＡ明显升高,鸡冠花组和牛磺酸组经过预防性给药,与对照组比血脂和ＭＤＡ明显降低（Ｐ＜０．０５）,肝组织经病理检查：与实验组相比,对照组肝脏切ＸＭ下观脂肪空泡增多,肉眼观肝脏明显肿大,肝／体比值明显增加（Ｐ＜０．０１）．结论鸡冠花乙醇提取物和牛磺酸具有降低血脂、ＭＤＡ及预防脂肪肝的作用．     

牛磺酸抑制实验性肝纤维化大鼠细胞外基质沉积

目的研究牛磺酸抗肝纤维化作用。大法用四氯化碳（ＣＣＩ４）制备肝纤维化模型;免疫组化检测肝Ⅰ、Ⅲ、Ⅵ型胶原和透明质酸、层粘连素沉积;Ｎｏｒｔｈｅｒｎｂｌｏｔ杂交检测肝Ⅰ、Ⅲ型前胶原、组织金属蛋白酶抑制因子－１（ＴＩＭＰ—１）ｍＲＮＡ含量。结果ＣＣＩ４肝纤维化大鼠肝脏Ⅰ、Ⅲ、Ⅵ型胶原、透明质酸和层粘连素染色明显增多;Ⅰ、Ⅲ型前胶原、ＴＩＭＰ－１ｍＲＮＡ显著增加。牛磺酸处理的大鼠,上述各指标的阳性染色明显减少,并可明显抑制Ⅰ、Ⅲ型前胶原基因表达,而对ＴＩＭＰ—１ｍＲＮＡ却无明显影响。结论牛磺酸对ＣＣＩ４诱导的大鼠肝纤维化具有保护作用,可明显抑制纤维生成与沉积。提示它对防治肝纤维化有一定的临床意义。     

牛磺酸和甘糖酯对糖尿病大鼠自由基防御机能和肾脏功能的影响

目的：探讨牛磺酸和甘糖酯对糖尿病（ＤＭ）大鼠体内自由基防御机能和肾功能的影响。方法：牛磺酸（３００ｍｇ／ｋｇ ＢＷ）甘糖酯（１００ｍｇ／ｋｇ ＢＷ）给予ＤＭ大鼠３周后,检查体内抗氧化酶活性,抗氧化物质水平和肾脏功能。